The Commonwealth of Virginia's Department of Geology and Mineral Resources has their offices in Charlottesville, Virginia. Outside their building is an exceptional collection of large rock samples from across the state. Samples include igneous, sedimentary, and metamorphic rocks from all five physiographic provinces, and spanning more than a billion years of geologic time. This gigapan was shot on April 14, 2011, during the lunch break of the DGMR's annual "Geology of Virginia" symposium. A full guide to the rocks in the garden is published online by the DGMR at:
www.dmme.virginia.gov/DMR3/dmrpdfs/vamin/VM 48_2_3.pdf
The map of the garden in that document shows that this gigapan was shot from the sidewalk between the two samples of #31, the Leesburg Conglomerate and #35, the Antietam Formation quartzite, with its characteristic linear Skolithos trace fossils.
A blog post describing some of the rocks is online at:
www.nvcc.edu/home/cbentley/geoblog/2008/12/rock-garden.html